Hey guys,
I have searched and searched but can't find any information about this topic.

Before my swap my A/c worked flawlessly no issues at all.
I swapped in a B20b and used a ob2b to obd1 jumper from rywire and a chipped P28 running Crome.

Now when I use the A/C it will get nice and cold then cycle off and stay off till it gets almost unbearable in the car then kick on and keeps doing this long cycle stuff.

Has anyone had this issue before? If so is it a side effect of chipping the p28?

Like I said everything worked fine before swap, A/C would keep the cabin nice and cool.

If not an ECU issue what else would cause this?

 

If possible, swap another chipped ECU into your car or use your ECU in another car with A/C.

The A/C compressor is controlled by the ECU and I've repaired a few that just didn't work but I've never come across one that introduces the "delay" you describe.

 

Well, I dont have anyway to do it.. Im using crome Gold bin with my RTP and Gold doesnt let me save anything to the computer. I'm almost thinking it maybe crome. I know in Neptune you can control the A/C duty cycle's and stuff I think...

I'm going to see if it also is effected by outside temp, it was really hot the day it was doing it.

 

I doubt the ecu is your problem.
1. Check your a/c for system proper pressure/levels.
2. Try bypassing the a/c pressure switch with a jumper wire to see if the "delay" is still there.

 

Got the same issue over here!
Just plugged the old P2P ecu and A/C starts working fine.
Haven't tried the switch jumper yet.

 

The A/C compressor is controlled by the ECU and I've repaired a few...

 

Got a chipped P28 (don't know for sure if is a real P28 board or just the label in the external case) that can't manage the A/C to work.
Measured Voltage between pins A9 and C5 in OBD2a side and is below 1V. According to service manual this is an ecu problem.
A/C works flawlessly with original P2P AT ECU and the B transmission plug disconnected. My car is AT to MT swapped.
I'm using OBD2a to OBD1 harness.
Any suggestion?
Thanks.

EDIT:
Issue solved. Connected A17 and C5 OBD2a wires together. A/C works now. I think the remain issue is that ECM doesn't enrich the mixture when A/C is on.